Slack-adjuster.



E. N. LUBURG.

SLACK ADJUSTER.

APPLICATION flLED MAY 6. 1914.

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WITNESSES INVENTOR E1]: wort/1 jVeJymzLubwzy;

E. N. LUBURG.

SLACK ADJUSTER.

APPLICATION mm MAY 6. 1914.

3,550, I Patented Dec. 7, 1915.

5 SHEETS-SHEET 2.

I IV V5 IV To I? Ellswartb M110): Zubw norm/5r E N. LUBURG.

SLACK ADJUSTER.

APPLICATION FILED MAY 6. 1914 1,163,550. Patented 'Dec. 7, 1915.

5 SHEETS-SHEET 3.

WIT/M8858 NINE/W06 E. N. L UBURG.

SLACK ADJUSTER.

APPLICATION FILED MAY 6. 1914.

1,163,550. Patented Dec. 7,1915.

5 SHEETS-SHEET 4.

WITH/E8858 34 v INVENTORY 33 E. N. LUBURG.

SLACK ADJUSTER. APPLICATION FILED MAY 6. 1914. 1.,163,55. PatentedDec.7,1915.

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SLACK-ADJUSTER.

Specification of Letters Patent.

Patented Doe. v, 1915.

Application filed May 6, 1914. Serial No. 836,788.

To all whom it may concern.

.Be it known that I, ELLSWORTH NELSON Leanne, a citizen of the UnitedStates, and a resident of Arlington, in thecounty of Baltimore and Stateof Maryland,. have invented a certain new and useful Improvement inSlack-Adjusters, of which thefollowing is a full, clear, and exactdescription, whereby anyone skilled in the art may make and use thesame.

The invention relates to what is ordinarily known as slack adjusters,that is, a device for taking up slack in a mechanical device ormechanism which is induced by wear or elongation of the parts from anycause whatsoever.

It relates more particularly to an adjusting device applicable to brakemechanisms and is shown herein as applied to an automobile brake, thisforming one of the best illustrations of its use-and operation. It isnot restricted in its use to brake mechanisms nor is it to be restrictedto automobile brakes as it obviously may be used with very materialadvantage in connection with mechanical brakes or air brakes.

The object of the invention is to provide a device which, during themovement of the mechanism to which it is attached, will antomaticallyadjust itself and said mechanism durin the natural operating movementsof said mechanism.

It is an object of the invention to compensate through the mechanism forany wear which may be occasioned by adjusting the mechanical parts of amechanism subject to conditions of wear so that any wear or slackoccasioned by the movement of the parts in one direction and underapplication and operation, will be immediately adjusted and compensatedfor by the return movement of the parts to a normal inoperativeposition.

It is the principal object of the invention to produce a device which,in its compensating or adjusting movements will adjust with precisionand indirect ratio to the wear.

Referring to the drawings: Figure 1 is a view in side elevation of thedevice as it is applied to a brake band of the contracting type. Fig. 2is a similar view-on reduced scale of the device as applied to the camor rock shaft of an expanding brake. In this application of the device,the adjusting rod is secured to a fixed stop on the casing. Fig. 2" is afragmentary view of the cam for expanding the brake shoes of the typeillustrated in Fig. 2. Fig. 3 is a view on onlarged scale of the deviceillustrated in Fig. 2, with parts of the connecting rod broken away toshow the sprin clevice. Fig. 4 is a sect1onal view on the inc 4-4 ofFig. 5. F g. 5 1s a sectional view on the line 5--5 of Fig. 3. Fig. 6 isa sectional view on the l1ne 66 of Fig. 5. Fig. 7 is a detail Viewpartially in section of the pinion and ratchet illustrated in Fig. 6.Fig. 8 is a detail rear face view of the bevel, gear and ratchetillustrated in Fig. 5. Fig. 9 is a longitudinal section of the bevel,gear, ratchet, pin- 10D and shaft. Fig. 10 is a detail View in sectionof the adjusting shaft segment. Fig. 11 1s a detail view of theadjustment for the ad usting lever illustrated at the left-of Fig. 10.Fig. 12 is a detail view of the stop disk and clutch at the right ofFig. 10.

It has not been an pncommon practice to employ adjusting devices forautomatically taking up slack to a certain degree which may occur inbrake rods and like devices which are used for applying brakes. By slackis meant the excess movement required on the brake lever and itsconnecting rod to bring the brake shoes or movableelement of the brakingdevice up to its set braking position with the cooperating brake drum orsimilar member. 1

It is one of the principal objects of the present invention to provide adevice which, with a single movement of the lever and brake rod oranalogous parts will secure a positive and perfect adjustment, taking upexactly the amount of excess movement of said mechanism which has beenpermitted by the wear of the parts. As an instance, a connecting rodbetween the brake band and a brake lever must have a free play ormovement equal to the movement required to move the brake band from itsslack or open position to its full on position in contact with thecooperating brake members. This movement should always remain fixed tosecure the best results and provide against drag of the brake shoes orbands. Obviously, upon wearing of the brake drum or brake bands duringthe application of the brake, the brake rod, on an application of thebrake bands, will move throu h a greater lineal distance. The inventionerein described contemplates the immediate adjustment of said brake rodto alwa s maintain a fixed minimum movement 0 the rod in applying thebrakes and if wear is occasioned, as the brake is applied, during theforward movement of the brake rod or any movement in applying thebrakes, that wear will be immediately compensated for by a shortening ofthe connections or a re-adjust- No. 752,414 filed March 6, 1913 andSerial No. 682,910, filed March 11, 1912 I have described a mechanismfor shortening the connecting or brake rod always in exact ratio to itsexcess movement due to wear. In the device herein described, I show amechanism which may be applied directly to the braking devices and in ameasure taking the place of the ordinary brake lever which operatescams, toggles or other devices for applying the brake bands or brakeshoes to the brake drum or wheel. This device when used, giv-' ing anaccurate and determinate adjustment for each brake, obviates thenecessity of utilizing equalizing bars between brakes when used inmultiple relation on different wheels.

In the accompanying drawings in Fig. 1, the device is shown as appliedto a contracting brake such as is commonly employed on the exterior of abrake drum, while in Fig. 2 the mechanism is illustrated as applied toan internal brake. The mechanism inclosed within the casing 1 in eithercase is of the same form and is hereinafter described in detail. It willbe noted that the only difference in the two applications of the deviceillustrated in Figs. 1 and 2 resides in the arrangement of the exteriorconnection.

In Fig. 1 the numeral 2 denotes one side of a brake ring or band and 3the adjoining side. The side or end 2 is providedwith a rocker support 4in which is pivotally arranged a rocker arm 5, one side of whichterminates in the brake lever arm 6 which is connected to the brake rod7 that is connected forward with any suitable brake lever. One end 8 ofa rocker arm is connected through a link 9 with an arm 10 which is fastupon the main adjustable shaft 11 which, as hereinafter described indetail, changes its position and varies the position of the arm 10,connecting link 9 and rock arms 8 and 6 whenever any excess movement ofthe brake rod 7 has taken place, such as might be due to wear of thebrake band 2, 3, which would permit slack when the brake band wasreleased. The numeral 12 denotes an adjusting bar which at one end iscon- 1,1es,sao

nected with an adjusting lever 13 and at its opposite end is suitablyconnected as at 14 with any fixed point adjacent to the end 2 of thebrake band. It will be noted that the device is merely hung upon oneside 3 of the brake band as by being secured to the bracket 15 and theusual links and brake connections ordinarily attached to the oppositeend of the brake band are connected to the device through the lever 10.

In Fig. 2 the main adjustable shaft 11 represents the end of the tappetor cam shaft of an internal brake which projects through the casing andmechanism, said casing and mechanism having an extended arm .16 whichtakes the place of the ordinary brake lever arm such as 6 which isillustrated in Fig. 1. In the case of Fig. 2, the adjusting lever 13 isconnected through the rod 12 exactly as in Fig. 1 with a fixed stop 17shown as a stud projecting from the brake housing 18 of the wheel 19.The wheel 19 shows the more modern type of brake struc ture in which thebrake shoes are arranged within a drum 20 and pivotally hung to a fixedbracket as at 21 with their free ends arranged to be expanded by a cam22, the shaft of which is illustrated as the shaft 11, projectingthrough the adjusting mechanism hereinafter described in detail. Theadjusting device has all of its main parts arranged within a three-partcasing consisting of a capped part 23 which forms a bearing for anadjusting shaft 24 and the main split casing 25, 26, which incloses themechanism and is provided with an extended arm 16 illustrated in Figs. 2and 3. Within the casing is arranged a worm-gear 27 which has asubstantial bearing in the casing and is arranged to be fitted over andsecured to the tappet shaft 11 and applied as in Fig. 2 or to the shaft11 of Fig. 1, which bears the short lever 10. 1

When arranged as illustrated in Fig. 2, the tappet shaft 11 is keyed tothe spiral or worm gear segment 27 and this segment meshes with a worm28 preferably formed integral with a worm shaft 29 which, adjacent toits lowerend, is provided with a pinion 30 loosely mounted upon theshaft 29 but locked thereto by a toothed member 31 which engages atoothed member 32 fast on the pinion 30. The member 31 is pro vided witha squared opening which fits over the squared end 33 of the shaft 29 andthe toothed members are held in locked position by a tubular nut 34which is screwed into the lower end of the casing. Upon'removal of thetubular nut 34, the toothed member 31 will drop away from its engagementwith the member 32 and by applying a wrench to the squared end 33, theworm shaft 29 may be turned to rotate the segment 27 and tappet shaft11. This is only done in re-adjusting the device after it is compensatedfor wear. Such an adjustment is used when applyin new brake shoes orre-lining the brakes. he inion 30 meshes with a gear which is he (1against movement in one direction by a spring detent 36 which engagesteeth 37 formed on the under side of the gear. This gear 35 is securedto a beveled pinion 38 which is mounted upon the same shaft as the gearv35. The beveled pinion 38 meshes with a. beveled gear 39 which isloosely mounted upon a shaft 40 which shaft has a hub 41 provided withratchet teeth arranged to engage ratchet teeth formed upon a member 42which slides within the rear face of the beveled gear 39. Springs 43normally hold the ratchet teeth in engagement. The ratchet member 42 issquared or may be of any angular formation and fits a recess of asimilar form in the rear of the gear 39. The shaft 40 also bears fixedthereon a pinion 44 which meshes with the segmental gear 45 and thissegmental gear 45 is keyed to the adjusting shaft 46 which bears theadjusting lever 13. The adjusting lever 13 is normally loose upon theshaft 46 and at all times mayhave a limited movement with referencethereto dependent uponthe position of an adjustable stop which consistsof a screw 47 passing through an extension at one side of the axis ofthe lever 13 and adjustably arranged with reference to the beveledopening 48 formed through a ring 49 fixed ,with reference to a sleeve50. The sleeve 50 is provided at one end with a disk 51 best illustratedin Figs. 10 and 12 and opposed to said disk 51 is a disk 52 fast uponthe shaft 46. The disk 51 is slotted as at 53 and a )in 54 projects fromthe disk 52 into said slot. Said disk 51 is cut away as at 56 so that arecess is formed between said cut away portion and between the disk 52and a thrust washer 57 to receive a pair of clutch balls 58. The disk 52is provided with cam surfaces 59, 60 which are engaged by the clutchballs 58, said balls being normally held against their clutch faces byan intermediate spring 61.

opening 48 in the collar 49 provides, in conjunction with the pin 47,for various adjustments to permit a free movement of the lever 13. Thisfree movement of the lever 13 is to permit a movement of the main brakerod such as is required to move the braking parts from the off to the onposition and obviously, this may be varied to suit the exigencies of anyparticular case so that the device is applicable to any brake mechanismby being properly adjusted and there will be no adjusting movements ofthe parts until the brake rod has exceeded the ordinary movement of thebrake rod required to apply the brake.

The operation of the parts above described is identical in anyapplication of the device It will be observed that the beveled whichoperates as follows: With the adjusting lever 13 having a permissiblefree movement, the brake lever 16 may, upon a pull of the brake rod 7rock the device and the tappet shaft 11 and no motion will betransmitted to or through the various gears in train with the adjustableworm gear segment 27. As soon as wear occurs upon the brake shoes orappurtenant parts, it is obvious that the brake rod 7 will move forwarda greater distance than is normally permitted by a free movement allowedthe adjusting lever 13 through its adjusting screw 47 and the beveledslot or opening 48.

This will rock the device upon the shaft 11 to an abnormal extent andthe movement will increase so long as the brake shoes or analogous partscontinue to wear. This excess movement will be communicated to thesegmental gear 45 in the following manner. The adjusting lever 13 beingconnected to a fixed stop by its rod 12 permits the normal oscillationof the device on its main shaft 11 until the pin 47 brings up againstone side 48 of the slotted opening 48 of the ring 49. Thereupon thesleeve 50 will be rotated until the disk 51 moves one of the balls 58away from the cam surface 60. One end of the slot 53 now engages the pin54 and rotates the shaft 46 with its segmental gear 45. The rotation ofthe gear 45 rotates the pinion 44 in the direction illustrated by thearrow in Fig. 5 and slips the ratchet teeth of the member 41 withreference to the ratchet teeth, of the member 42 without turning thegear train 39, 38, 35, 30, 28 and 27 When the brake rod isreleased afterits excessive movement, the return oscillating movement of the devicewill cause a. locking of the adjusting lever 13 with reference to thesegmental gear 45 and thereupon said gear will transmit movement to thepinion 44 in a reverse direction from that indicated by the arrow inFig. 5 and thereupon the beveled gear 39 will rotate the beveled pinion38 and spur gear 35 which in turn rotates the pinion 30, worm shaft 29and worm 28 and thus rotates the segmental worm gear 27. This obviouslywill change the position of the tappet shaft 11 by rotating it and willcompensate for the excess movement of the brake rod 7 and connectedparts. This adjusting will take place until the brake parts arecompletely worn out and there will always be exactly the same slack orlost movement for the off and on position of the brake. When it isdesired to renew the brake shoes or linings of the brakes, the tubularcap nut 34 is removed from the casing and the key is applied to thesquared end 33 of the worm shaft 29. This shaft may then be turned torotate the worm gear 27 back to its initial position illustratedin Fig.6. During the rotation of'this shaft toward the left, the

ratchet member 31 is outof engagement with the cooperating member 32 andtherefore no motion is transmitted to the gear 35 and the train of gearsconnected therewith. The proportioning of the gear trains is such thatthe excess movement of the parts due to wear on the application of thebrake is compensated for exactly by a backward rotation of the deviceupon a rearward 19 movement of the brake rod and connected parts. It isobvious from this that a constant clearance will always be maintainedfor the brake mechanism. The whole device isapplicable as a unit to thetappet 5 shaft or rock shaft when used as illustrated in the drawingsand during the application of the brakes rocks the tappet shaft of Fig.2 or the brake arm of Fig. 1 exactly as the ordinary connecting. leverwould do. Upon the reverse movement of the brake rod, if any wear hastaken place, the tappet shaft is rotated to an exact degree tocompensate for the excessmovement occasioned by the wear and thus theminimum amount 5 of loose play, lost movement, or such movement as isrequ1red to fully relieve the brakes, is always maintained within fixedlimits, no matter how much the parts may wear.

Obviously, the exact details of the mechanism might be varied to aconsiderable extent without departing from the spirit or intent of theinvention and of course the device might be applied to the adjustment of5 any mechanism where it is desired to maintain a fixed constant of freemovement and compensate for excess movements due to wear and'similarcauses.

What I claim as my invention and desire 40 to secure by Letters Patentis:

1. A slack adjuster comprising a casing and support, an adjustable shaftmounted therein, as oscillatory adjusting shaft, a gear trainintermediate said shafts and nor- 5 mally locking the adjustable shaftagainst movement with reference to the casing and support, means forpermitting free oscillation of the adjusting shaft inone direction andmeans for locking said shaft and gear train for rotating the adjustableshaft when the oscillating shaft is moved in the opposite direction.

2. A slack adjuster comprising a casing and support, an adjustableshaft, a worm gear and worm for moving said shaft, an oscillatoryadjusting shaft, a gear train intermediate said shaft and worm, clutchdevices permitting a free oscillation of said oscillatory shaft in onedirection without so transmitting movement to the worm and means fortransmitting movement of said oscillatory shaft to the worm for rotatingthe adjustable shaft during oscillation in the opposite direction. '953. A slack adjuster comprising a casing,

an adjustable shaft normally locked with reference to said casing, aworm and worm gear for rotating said shaft, a gear train connected withsaid worm, an oscillatory shaft connected with the gear train, a lever 7for actuating said shaft an clutch devices permitting a free movement ofthe lever in one direction and locking said lever to the gear train tomove the latter during oscillation in the opposite direction.

4. A slack adjuster comprising a casing, an adjustable tappet shaftextending therethrough and normally locked against movement withreference to the casing by a gear train, a gear train adapted to rotatesaid 30 tappet shaft, an adjusting shaft operatively connected with saidgear train, clutch devices permitting an oscillation of said shaft inone direction without transmitting movement to the tappet shaft anddevices for locking said shaft and gear train to rotate the tappet shaftduring an oscillation of the adjusting shaft in the opposite direction.

5. A slack adjuster comprising a casing, a rotatable adjustable shaftmounted therein, a gear train for rotating said shaft, an oscillatoryadjusting shaft connecting with the gear train, a lever for oscillatingsaid shaft, said lever having a free movement with reference to theshaft, means for adjusting the degree of said movement, clutch devicespermitting movement of the oscillatory shaft' in one direction with theadjustable shaft immovable and devices for clutchingthe lever shaft andgear train for to 10 tating the ad'ustable shaft during oscillation ofthe a justing shaft in the opposite direction.

6. A slack adjuster comprising a casing, an adjustable shaft mountedtherein, a worm gear segment secured to said shaft, a worm meshing withsaid gear segment, an oscillatory adjusting shaft, a gear trainintermediate said shaft and worm for rotating said worm duringoscillation of the adjusto ing shaft in one direction, clutch devicespermitting free oscillation of the shaft with reference to the worm andmeans for oscillating the adjusting shaft.

7 In a slack adjuster embodying an adjustable shaft and an oscillatoryadjusting shaft, a lever for oscillating the latter, a disk borne uponthe oscillatory shaft and provided with a beveled perforation, anadjustable pin arranged upon the lever and projecting into saidperforation, said pin and beveled opening determining by their relativeposition the free movement of the lever with reference to the shaft.

8. In a device of the character described embodying an adjustable shaftand an oscillatory adjusting shaft with an intermediate gear train formoving the former upon certain movements of the latter, a segmental gearmounted upon the oscillatory shaft, a 13 and adjustable shaft mountedtherein and an oscillatory adjusting shaft, a gear train connecting saidshafts and including a worm gear, worm and worm shaft, automatic meansfor rotating the worm shaft through the gear train and means fordisconnecting said worm shaft from the gear train to per- 1:,

mit manual rotation of the worm'and worm gear.

ELLSWORTH NELSON LUBURG.

Witnesses:

N. EDWARD KIRK, CHAS. HOFFMAN.

